The following U.S. Patents are incorporated herein by reference.
U.S. Pat. No. 7,370,611 discloses a cooling system for a marine propulsion device that provide a bypass loop around a cooling pump that allows the flow of cooling water through certain components to be reduced or increased as a function of the temperature of those components while causing a full flow of cooling water to flow through other selected heat emitting devices. Using this configuration of components and bypass conduits, the operating condition of the cooling water pump can be continually monitored, including the condition of its flexible vanes. By observing the effective cooling capacity of the system under conditions with the bypass valve open and closed, the effectiveness of the cooling water pump can be assessed and a suggestion of maintenance can be provided.
U.S. Pat. No. 7,476,135 discloses a cooling system for a marine vessel that is configured to allow all cooling water to flow out of the cooling circuit naturally and under the influence of gravity when the marine vessel is removed from the body of water. All conduits of the cooling circuit are sloped downwardly and rearwardly from within the marine vessel to an opening through its transom. Traps are avoided so that residual water is not retained within locations of the cooling system after the natural draining process is complete. The opening through the transom of the marine vessel is at or below all conduits of the cooling system in order to facilitate the natural draining of the cooling system under the influence of gravity and without the need for operator intervention.
U.S. Pat. No. 7,503,819 discloses a cooling system for a marine propulsion device that provides a closed portion of the cooling system, which recirculates coolant through the engine block and cylinder head, the exhaust manifold, and the exhaust elbow. It provides a pressure relief cap connected to the exhaust elbow and a low velocity portion of the coolant jacket of the exhaust elbow to facilitate the release of gas and coolant when pressures exceed a preselected magnitude.
U.S. Pat. No. 7,585,196 discloses a cooling system for a marine propulsion device that provides a transom opening that is sufficiently low with respect to other components of the marine propulsion device to allow automatic draining of all cooling water from the system when the marine vessel is removed from the body of water in which it had been operating. The engine cooling passages and other conduits and passages of the cooling system are all located at positions above the transom opening. The system provides automatic draining for a marine cooling system that is an open system and which contains no closed cooling portions.
U.S. Pat. No. 8,298,025 discloses cooling systems and methods for hybrid marine propulsion systems. A first cooling circuit is arranged to convey raw cooling water through an internal combustion engine and to at least one drive component of a drive unit for the marine propulsion system. A second control circuit is arranged to convey raw cooling water through an electric motor. The system is arranged such that raw cooling water in the second cooling circuit is conveyed to the first cooling circuit to cool the drive component without cooling the component of the internal combustion engine.
U.S. Pat. No. 8,402,930 discloses a cooling system for a marine engine that is provided with various cooling channels and passages which allow the rates of flow of its internal streams of water to be preselected so that heat can be advantageously removed at varying rates for different portions of the engine. In addition, the direction of flow of cooling water through the various passages assists in the removal of heat from different portions of the engine at different rates so that overheating can be avoided in certain areas, such as the exhaust manifold and cylinder head, while overcooling is avoided in other areas, such as the engine block.
U.S. Pat. No. 8,479,691 discloses a cooling system for a marine engine provided with various cooling channels which allow the advantageous removal of heat at different rates from different portions of the engine. A split flow of water is conducted through the cylinder head, in opposite directions, to individually cool the exhaust port and intake ports at different rates. This increases the velocity of coolant flow in the downward direction through the cylinder head to avoid the accumulation of air bubbles and the formation of air pockets that could otherwise cause hot spots within the cylinder head. A parallel coolant path is provided so that a certain quantity of water can bypass the engine block and avoid overcooling the cylinder walls.
U.S. Pat. No. 8,500,501 discloses an outboard marine drive that includes a cooling system drawing cooling water from a body of water in which the outboard marine drive is operating, and supplying the cooling water through cooling passages in an exhaust tube in the driveshaft housing, a catalyst housing, and an exhaust manifold, and thereafter through cooling passages in the cylinder head and the cylinder block of the engine. A 3-pass exhaust manifold is provided. A method is provided for preventing condensate formation in a cylinder head, catalyst housing, and exhaust manifold of an internal combustion engine of a powerhead in an outboard marine drive.
U.S. Pat. No. 8,540,536 discloses a cooling system for a marine engine having an elongated exhaust conduit comprising a first end receiving hot exhaust gas from the marine engine and a second end discharging the exhaust gas; and an elongated cooling water jacket extending adjacent to the exhaust conduit. The cooling water jacket receives raw cooling water at a location proximate to the second end of the exhaust conduit, conveys raw cooling water adjacent to the exhaust conduit to thereby cool the exhaust conduit and warm the raw cooling water, and thereafter discharges the warmed cooling water to cool the internal combustion engine.